/*
 * JSMN json parser.
 */
#include <stdlib.h>
#include "jsmn.h"

/**
 * Allocates a fresh unused token from the token pull.
 */
static jsmntok_t *jsmn_alloc_token(jsmn_parser * parser,
                                   jsmntok_t * tokens, size_t num_tokens)
{
    jsmntok_t *tok;
    if (parser->toknext >= num_tokens) {
        return NULL;
    }
    tok = &tokens[parser->toknext++];
    tok->start = tok->end = -1;
    tok->size = 0;
#ifdef JSMN_PARENT_LINKS
    tok->parent = -1;
#endif
    return tok;
}

/**
 * Fills token type and boundaries.
 */
static void jsmn_fill_token(jsmntok_t * token, jsmntype_t type,
                            int start, int end)
{
    token->type = type;
    token->start = start;
    token->end = end;
    token->size = 0;
}

/**
 * Fills next available token with JSON primitive.
 */
static jsmnerr_t jsmn_parse_primitive(jsmn_parser * parser, const char *js,
                                      jsmntok_t * tokens, size_t num_tokens)
{
    jsmntok_t *token;
    int start;

    start = parser->pos;

    for (; js[parser->pos] != '\0'; parser->pos++) {
        switch (js[parser->pos]) {
#ifndef JSMN_STRICT
            /* In strict mode primitive must be followed by "," or "}" or "]" */
        case ':':
#endif
        case '\t':
        case '\r':
        case '\n':
        case ' ':
        case ',':
        case ']':
        case '}':
            goto found;
        }
        if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
            parser->pos = start;
            return JSMN_ERROR_INVAL;
        }
    }
#ifdef JSMN_STRICT
    /* In strict mode primitive must be followed by a comma/object/array */
    parser->pos = start;
    return JSMN_ERROR_PART;
#endif

 found:
    token = jsmn_alloc_token(parser, tokens, num_tokens);
    if (token == NULL) {
        parser->pos = start;
        return JSMN_ERROR_NOMEM;
    }
    jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
#ifdef JSMN_PARENT_LINKS
    token->parent = parser->toksuper;
#endif
    parser->pos--;
    return JSMN_SUCCESS;
}

/**
 * Filsl next token with JSON string.
 */
static jsmnerr_t jsmn_parse_string(jsmn_parser * parser, const char *js,
                                   jsmntok_t * tokens, size_t num_tokens)
{
    jsmntok_t *token;

    int start = parser->pos;

    parser->pos++;

    /* Skip starting quote */
    for (; js[parser->pos] != '\0'; parser->pos++) {
        char c = js[parser->pos];

        /* Quote: end of string */
        if (c == '\"') {
            token = jsmn_alloc_token(parser, tokens, num_tokens);
            if (token == NULL) {
                parser->pos = start;
                return JSMN_ERROR_NOMEM;
            }
            jsmn_fill_token(token, JSMN_STRING, start + 1, parser->pos);
#ifdef JSMN_PARENT_LINKS
            token->parent = parser->toksuper;
#endif
            return JSMN_SUCCESS;
        }

        /* Backslash: Quoted symbol expected */
        if (c == '\\') {
            parser->pos++;
            switch (js[parser->pos]) {
                /* Allowed escaped symbols */
            case '\"':
            case '/':
            case '\\':
            case 'b':
            case 'f':
            case 'r':
            case 'n':
            case 't':
                break;
                /* Allows escaped symbol \uXXXX */
            case 'u':
                /* TODO */
                break;
                /* Unexpected symbol */
            default:
                parser->pos = start;
                return JSMN_ERROR_INVAL;
            }
        }
    }
    parser->pos = start;
    return JSMN_ERROR_PART;
}

/**
 * Parse JSON string and fill tokens.
 */
jsmnerr_t jsmn_parse(jsmn_parser * parser, const char *js, jsmntok_t * tokens,
                     unsigned int num_tokens)
{
    jsmnerr_t r;
    int i;
    jsmntok_t *token;

    for (; js[parser->pos] != '\0'; parser->pos++) {
        char c;
        jsmntype_t type;

        c = js[parser->pos];
        switch (c) {
        case '{':
        case '[':
            token = jsmn_alloc_token(parser, tokens, num_tokens);
            if (token == NULL)
                return JSMN_ERROR_NOMEM;
            if (parser->toksuper != -1) {
                tokens[parser->toksuper].size++;
#ifdef JSMN_PARENT_LINKS
                token->parent = parser->toksuper;
#endif
            }
            token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
            token->start = parser->pos;
            parser->toksuper = parser->toknext - 1;
            break;
        case '}':
        case ']':
            type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
#ifdef JSMN_PARENT_LINKS
            if (parser->toknext < 1) {
                return JSMN_ERROR_INVAL;
            }
            token = &tokens[parser->toknext - 1];
            for (;;) {
                if (token->start != -1 && token->end == -1) {
                    if (token->type != type) {
                        return JSMN_ERROR_INVAL;
                    }
                    token->end = parser->pos + 1;
                    parser->toksuper = token->parent;
                    break;
                }
                if (token->parent == -1) {
                    break;
                }
                token = &tokens[token->parent];
            }
#else
            for (i = parser->toknext - 1; i >= 0; i--) {
                token = &tokens[i];
                if (token->start != -1 && token->end == -1) {
                    if (token->type != type) {
                        return JSMN_ERROR_INVAL;
                    }
                    parser->toksuper = -1;
                    token->end = parser->pos + 1;
                    break;
                }
            }
            /* Error if unmatched closing bracket */
            if (i == -1)
                return JSMN_ERROR_INVAL;
            for (; i >= 0; i--) {
                token = &tokens[i];
                if (token->start != -1 && token->end == -1) {
                    parser->toksuper = i;
                    break;
                }
            }
#endif
            break;
        case '\"':
            r = jsmn_parse_string(parser, js, tokens, num_tokens);
            if (r < 0)
                return r;
            if (parser->toksuper != -1)
                tokens[parser->toksuper].size++;
            break;
        case '\t':
        case '\r':
        case '\n':
        case ':':
        case ',':
        case ' ':
            break;
#ifdef JSMN_STRICT
            /* In strict mode primitives are: numbers and booleans */
        case '-':
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        case 't':
        case 'f':
        case 'n':
#else
            /* In non-strict mode every unquoted value is a primitive */
        default:
#endif
            r = jsmn_parse_primitive(parser, js, tokens, num_tokens);
            if (r < 0)
                return r;
            if (parser->toksuper != -1)
                tokens[parser->toksuper].size++;
            break;

#ifdef JSMN_STRICT
            /* Unexpected char in strict mode */
        default:
            return JSMN_ERROR_INVAL;
#endif

        }
    }

    for (i = parser->toknext - 1; i >= 0; i--) {
        /* Unmatched opened object or array */
        if (tokens[i].start != -1 && tokens[i].end == -1) {
            return JSMN_ERROR_PART;
        }
    }

    return JSMN_SUCCESS;
}

/**
 * Creates a new parser based over a given  buffer with an array of tokens 
 * available.
 */
void jsmn_init(jsmn_parser * parser)
{
    parser->pos = 0;
    parser->toknext = 0;
    parser->toksuper = -1;
}
